99 classic 4x4 113 miles

trying to track down high speed vibration

How do you tell if you have a bad tranny mount?

I can grab the rear driveshaft in front of transfercase and move transfer case left to right 1/4 to 1/2 inch . Is this normal? Mount is covered in grease n oil Its a little spongy but not bad.

How hard is it to replace mount?

thanks

Jacksonbase

 

No. It's not normal. Tighten up your transfer case bolts.

 

I'd replace your mount anyway.

They're roughly $30 or so at most local chain auto parts store.

I'm the kind of person that just replaces stuff due to mileage anyway, even if it's fine.

My trans mount wasn't "bad" but I replaced it and did notice a difference.

 

Do you motor mounts at the same time.

 

+1, make sure all the bolts are still there.

 

This.

Also go get Grade 8 bolts to replace the factory ones. Motor mount bolts are prone to snapping if you aren't careful.